U.S. patent application number 15/207939 was filed with the patent office on 2016-11-03 for method for loading a stent into a delivery system.
The applicant listed for this patent is BOSTON SCIENTIFIC SCIMED, INC.. Invention is credited to CLAUDE O. CLERC, STEPHAN P. MANGIN, EMILY E. RUSK, MICHAEL E. ZUPKOFSKA.
Application Number | 20160317334 15/207939 |
Document ID | / |
Family ID | 40029168 |
Filed Date | 2016-11-03 |
United States Patent
Application |
20160317334 |
Kind Code |
A1 |
RUSK; EMILY E. ; et
al. |
November 3, 2016 |
METHOD FOR LOADING A STENT INTO A DELIVERY SYSTEM
Abstract
Methods for assembling a stent delivery system are provided, as
well as the stent delivery assemblies and devices formed by such
methods. Also provided is a method for loading a stent into a
delivery system.
Inventors: |
RUSK; EMILY E.; (Boston,
MA) ; MANGIN; STEPHAN P.; (Austin, TX) ;
CLERC; CLAUDE O.; (Marlborough, MA) ; ZUPKOFSKA;
MICHAEL E.; (Rockland, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BOSTON SCIENTIFIC SCIMED, INC. |
Maple Grove |
MN |
US |
|
|
Family ID: |
40029168 |
Appl. No.: |
15/207939 |
Filed: |
July 12, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11860075 |
Sep 24, 2007 |
9393137 |
|
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15207939 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/9522 20200501;
A61F 2250/0097 20130101; A61F 2/88 20130101; A61F 2002/9505
20130101; A61F 2/89 20130101; A61F 2/95 20130101; A61F 2/844
20130101; A61F 2250/0091 20130101; A61F 2/90 20130101; A61F
2250/006 20130101; A61F 2/962 20130101 |
International
Class: |
A61F 2/962 20060101
A61F002/962; A61F 2/89 20060101 A61F002/89; A61F 2/88 20060101
A61F002/88; A61F 2/844 20060101 A61F002/844; A61F 2/90 20060101
A61F002/90 |
Claims
1. A method for assembling a stent delivery system comprising:
inserting a distal portion of a distensible stent into a proximal
end of a first tubular member having a lumen extending
therethrough, wherein the distal portion of the stent is in a
constrained state and a proximal portion of the stent that is not
inserted into the first tubular member is in an unconstrained
state; and inserting a second elongate member into the proximal end
of the first tubular member, the second elongate member having a
stent-engaging portion, causing the stent-engaging portion to
engage the stent such that relative movement of the second elongate
member causes relative movement of the stent.
2. The method of claim 1, wherein movement of the second elongate
member towards a distal end of the first tubular member causes
concomitant movement of the stent towards the distal end of the
first tubular member.
3. The method of claim 2, wherein the stent is fully constrained
within the first tubular member when a distal end of the second
elongate member is aligned with the distal end of the first tubular
member.
4. The method of claim 1, wherein the proximal end of the first
tubular member includes a funnel shaped member, wherein the stent
is compressed from the unconstrained state to the constrained state
as the stent is inserted through the funnel shaped member into the
lumen of the first tubular member.
5. The method of claim 1, wherein the first tubular member includes
a visual marker for observing a position of the stent as the stent
is inserted.
6. The method of claim 5, wherein the stent does not extend beyond
the visual marker prior to engagement with the second elongate
member.
7. The method of claim 5, wherein a distal end of the stent is
aligned with the visual marker upon partial insertion of the stent
into the first tubular member.
8. The method of claim 1, further comprising attaching a tip
component to a distal end of the second elongate member.
9. The method of claim 8, wherein the tip component is attached
after the second elongate member is inserted into the first tubular
member.
10. The method of claim 1, wherein the stent-engaging portion on
the second elongate member includes at least one raised member
extending radially away from an outer surface of the second
elongate member, wherein the at least one raised member engages an
inner surface of the stent.
11. A method for loading a stent into a sheath delivery system
comprising the steps of: inserting a distensible stent into a
proximal end of a first tubular member of a sheath delivery system
such that a distal portion of the stent is in a constrained state
within a lumen of the first tubular member and a proximal portion
of the stent remains outside the first tubular member is in an
unconstrained state; passing a second elongate member into a lumen
of the stent such that the second elongate member becomes
releasably engaged to an inner surface of the stent; and moving the
second elongate member toward a distal end of the first tubular
member thereby advancing the stent toward the distal end of the
first tubular member and compressing the proximal portion of the
stent as the stent is fully inserted into the lumen of the first
tubular member.
12. The method of claim 11, wherein inserting the stent into the
lumen of the first tubular member includes inserting the stent
until a distal end of the stent is aligned with a visual marker on
the first tubular member.
13. The method of claim 11, wherein the second elongate member
becomes releasably engaged to the stent by engaging an anchor on an
outer surface of the second elongate member with the inner surface
of the stent.
14. The method of claim 11, further comprising attaching a delivery
system tip to a distal end of the second elongate member.
15. The method of claim 14, wherein the delivery system tip is
attached after the second elongate member is fully inserted into
the first tubular member.
16. The method of claim 11, wherein the proximal end of the first
tubular member includes a funnel shaped member, wherein the stent
is compressed from the unconstrained state to the constrained state
as the stent is inserted through the funnel shaped member into the
lumen of the first tubular member.
17. A method for assembling a stent delivery system comprising:
inserting a distal portion of an unconstrained distensible stent
into a funnel shaped handle disposed at a proximal end of a first
tubular member having a lumen extending therethrough; compressing
the distal portion of the stent into a constrained state as the
distal portion enters the lumen while a proximal portion of the
stent outside the first tubular member remains in an unconstrained
state; inserting a distal end of a second elongate member into a
lumen of the stent and into the funnel shaped handle, the second
elongate member having a stent-engaging portion; moving the second
elongate member into the lumen of the first tubular member, causing
the stent-engaging portion to engage the stent; and advancing the
second elongate member with the stent engaged thereto through the
lumen toward a distal end of the first tubular member, thereby
compressing the proximal portion of the stent into the constrained
state.
18. The method of claim 17, wherein the stent-engaging portion on
the second elongate member includes at least one raised member
extending radially away from an outer surface of the second
elongate member, wherein the at least one raised member engages an
inner surface of the stent.
19. The method of claim 17, further comprising attaching a tip
component to the distal end of the second elongate member.
20. The method of claim 19, wherein the tip component is attached
after the second elongate member is inserted into the first tubular
member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 11/860,075, filed Sep. 24, 2007, the entire contents of which
is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to methods for assembling a stent
delivery system, as well as to stent delivery assemblies and
devices. This invention also relates to a method for loading a
stent into a stent delivery system.
BACKGROUND OF THE INVENTION
[0003] Stent delivery systems are well-known in the art. The
assembly of such delivery systems, however, often may be
complicated. In particular, although it is common practice to load
a stent into a sheath during assembly of a stent delivery system,
such loading often involves numerous steps and often requires the
use of multiple components (e.g., tools and fixtures) that are not
part of the stent delivery system. For example, currently available
stent delivery systems often require that a stent be loaded onto a
delivery system by means of a funnel, basket or other similar
device. However, it is often difficult and/or time-consuming to
assemble a stent onto a delivery system by such means. Accordingly,
there is a need for simplified methods of loading a stent into
stent delivery systems during assembly of the same.
SUMMARY OF THE INVENTION
[0004] The present invention is directed to methods for inserting a
stent into a stent delivery system, as well as to stent delivery
systems and devices. In particular, the present invention relates
to positioning a stent within a tubular structure by means of
another tubular structure for the purpose of deploying the stent in
a body. Moreover, the present invention relates to the resultant
assemblies and devices formed by positioning a stent within a
tubular structure in such a manner.
[0005] In one aspect of the invention, there is provided a device
for delivering a stent to a patient for implantation including: (i)
a first tubular structure having a proximal end, a distal end, and
a lumen extending therethrough; (ii) a second tubular structure
having a proximal end, a distal end, and a lumen extending
therethrough; (iii) a distensible stent having a proximal end and a
distal end; and (iv) a means for moving the stent. In such
embodiments, the stent may be disengagedly coupled to the inner
tubular structure by means of the means for moving the stent.
[0006] In another aspect of the invention, there is provided a
stent delivery system which includes a device for delivering a
stent to a patient for implantation including: (i) a first tubular
structure having a proximal end, a distal end, and a lumen
extending therethrough; (ii) a second tubular structure having a
proximal end, a distal end, and a lumen extending therethrough;
(iii) a distensible stent having a proximal end and a distal end;
and (iv) a means for moving the stent. In such embodiments, the
stent may be disengagedly coupled to the inner tubular structure by
means of the means for moving the stent. In another aspect of the
invention, there is provided a method for assembling a stent
delivery system including: (i) providing (a) a first tubular
structure having a proximal end, a distal end, and a lumen
extending therethrough; (b) a second tubular structure having a
proximal end, a distal end, a stent-engaging portion, and a lumen
extending therethrough; and (c) a distensible stent having a
proximal end and a distal end; (ii) inserting a portion of the
stent into the proximal end of the first tubular structure, wherein
the portion of the stent is in a constrained state relative to a
portion of the stent that is not inserted into the first tubular
structure; and (iii) inserting the second tubular structure into
the proximal end of the first tubular structure to cause the
stent-engaging portion to engage the stent such that relative
movement of the second tubular structure causes relative movement
of the stent.
[0007] In yet another aspect of the invention, there is provided a
method for loading a stent into a sheath delivery system including
the steps of: (i) providing a sheath delivery system including at
least one first tubular structure having a proximal end and a
distal end; wherein said proximal end of said tubular structure has
a handle attached thereto and wherein said tubular structure
includes a visual marker thereon; (ii) providing a distensible
stent having a distal end, a proximal end, and a lumen extending
therethrough; (iii) providing a second tubular structure having a
proximal end, a distal end, a stent-engaging portion, and a lumen
extending therethrough; (iv) passing the stent through the handle
and into the tubular structure of the sheath delivery system until
the distal end of the stent is aligned with the visual marker and
such that a portion of the stent is partially constrained within
the tubular structure; and (v) passing a second tubular structure
into the lumen of the stent such that the second tubular structure
becomes releasably engaged to the stent, wherein movement of the
second tubular structure toward the distal end of the first tubular
structure relative to the handle causes advancement of the stent
relative to the handle toward the distal end of the delivery
system.
[0008] The present inventive methods, devices, and stent delivery
systems are particularly useful for use with self-expanding stents,
including polymeric self-expanding stents, such as the Polyflex
stent, which includes polyethylene terephthalate (PET) filaments
having a silicone covering. In particular, because such polymeric
self-expanding stents will set if they are premounted on a delivery
device well in advance of implantation, such stents need to be
loaded onto a delivery device by a physician just prior to
implantation. The present inventive methods, devices, and stent
delivery systems allow for such loading immediately prior to
implantation.
[0009] These and other features of the invention will be better
understood through a study of the following detailed description
and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a tubular structure having a
stent partially constrained therein in accordance with the subject
invention.
[0011] FIG. 2 is a perspective view of the tubular structure of
FIG. 1 upon partial insertion of another tubular structure therein
in accordance with the present invention.
[0012] FIG. 3 is a perspective view of a tubular structure upon
complete insertion of another tubular structure therein to form a
fully-loaded stent assembly device in accordance with the present
invention.
[0013] FIGS. 4a-4c are cross-sectional views illustrating how a tip
and inner tubular member of the present invention may be attached
by means of a bump on the inner surface of tip.
[0014] FIG. 5 is a perspective view of an inner tubular structure
having a tip preassembled thereon being inserted into an outer
tubular structure having a stent partially loaded therein in
accordance with a method of the present invention.
[0015] FIG. 6 is a perspective view of the outer tubular structure
of FIG. 5 having the inner tubular structure shown in FIG. 5
partially inserted therein in accordance with a method of the
present invention.
[0016] FIG. 7 is a perspective view of the outer tubular structure
of FIG. 6 having the inner tubular structure shown in FIG. 5 fully
inserted therein to form a stent delivery device in accordance with
a method of the present invention.
[0017] FIGS. 8a-8e are perspective views illustrating how a tip and
inner tubular member of the subject invention may be attached by
means of a push-lock.
[0018] FIG. 9 is a perspective view illustrating how a tip and
inner tubular member of the subject invention may be attached by
means of a thread.
[0019] FIGS. 10a-10c are perspective views illustrating how a tip
and inner tubular member of the subject invention may be attached
by means of a clip.
[0020] FIGS. 11a-11c are perspective views illustrating how a tip
having collapsible hinges or fins may be inserted into an exterior
tubular structure of the subject invention.
[0021] FIG. 12 is a perspective view of an outer tubular structure
having an inner tubular structure and stent inserted therein,
wherein the stent is engaged to the inner tubular structure by
means of two stent-engaging portions.
[0022] FIG. 13 is a perspective view of an outer tubular structure
having an inner tubular structure and stent inserted therein,
wherein the inner tubular structure has a non-uniform diameter.
[0023] FIG. 14 is a longitudinal view of a wire stent suitable for
use in the present invention.
[0024] FIG. 15 is a longitudinal view of an atraumatic braided
stent for use in the present invention.
[0025] FIG. 16 is a longitudinal view of a zig-zag stent for use in
the present invention.
[0026] FIG. 17 is a longitudinal view of an alternate zig-zag stent
for use in the present invention.
[0027] FIG. 18 is a perspective view of a slotted stent for use in
the present invention.
[0028] FIG. 19 is a perspective view of a helical coil stent formed
of a single wound wire for use in the present invention.
[0029] FIG. 20 is a perspective view of a stent having an elongate
pre-helically coiled configuration for use in the present
invention.
[0030] FIG. 21 is a lengthwise cross-sectional view of a handle for
use with the present invention having a funneled or conical section
which has a rounded interior.
[0031] FIG. 22 is a longitudinal view of a stent which has a distal
end which is compressed by a structure or device.
[0032] FIG. 23 is a longitudinal view of a stent which has a distal
end which is compressed by means of a packaging material.
[0033] FIGS. 24-25 are perspective views of tubular structures
having a stent with a marker partially constrained therein in
accordance with a method of the subject invention.
[0034] FIG. 26 is a perspective view of an inner tubular structure
having an annular protruberance such as an o-ring thereon.
[0035] FIG. 27 is a perspective view of an inner tubular structure
having a flap thereon.
[0036] FIG. 28 is a perspective view of an inner tubular structure
having a pattern thereon.
[0037] FIG. 29 is a perspective view of an inner tubular structure
having a compressive and/or a tacky/sticky layer thereon.
[0038] FIG. 30 is a perspective view of an inner tubular structure
having a bump thereon.
[0039] FIG. 31 is a perspective view of an inner tubular structure
having an annular ridge thereon.
[0040] FIG. 32 is a perspective view of an inner tubular structure
having a divot therein.
[0041] FIGS. 33a-33c and 34a-34c are cross-sectional views
illustrating how a tip and inner tubular member of the subject
invention may be attached by means bumps and holes.
[0042] FIGS. 35a-35c are cross-sectional views illustrating how a
tip and inner tubular member of the subject invention may be
attached by means of a key and slot.
[0043] FIGS. 36a-36c are cross-sectional views illustrating how a
tip and inner tubular member of the subject invention may be
attached by means of barbs.
[0044] FIGS. 37a-37c are cross-sectional views illustrating how a
tip and inner tubular member of the subject invention may be
attached by means of ribs.
[0045] FIGS. 38a-38c and 39a-39c are cross-sectional views
illustrating how a tip and inner tubular member of the subject
invention may be attached by means of hooks and loops.
[0046] FIG. 40 is an exploded view of a stent for use in the
subject invention.
[0047] FIG. 41 is a cross-sectional view of the stent of FIG. 40
illustrating an outer graft covering disposed on the stent.
[0048] FIG. 42 is a cross-sectional view of the stent of FIG. 40
illustrating an inner graft lining disposed on the stent.
[0049] FIG. 43 is a cross-sectional view of the stent of FIG. 40
illustrating an inner graft lining and an outer graft covering
disposed on the stent.
[0050] FIG. 44 is a side planar view of a stent for use in the
subject invention illustrating a substantially longitudinally
straight stent.
[0051] FIG. 45 is a side planar view of a stent illustrating
outwardly flared ends according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0052] This subject invention pertains to assembly devices for
deploying a stent, or other device as described herein, in a bodily
passageway. Deployment may be achieved for medical applications
(particularly, endoscopic therapy) in the gastrointestinal tract,
the biliary tract, the urinary tract, and the respiratory tract.
Moreover, the assembly devices may be deployed in the neurological
system (e.g., in the brain) and in the cardiovascular system (e.g.,
in the heart, veins, and arteries). Reference to bodily passageways
may be to passageways in any of the aforementioned tracts and
systems or elsewhere in the body. The assembly devices are
particularly useful during endoscopy procedures in the
gastrointestinal tract and biliary tract. For instance, the
assembly devices are particularly useful for deployment in the
esophagus during endoscopy procedures.
[0053] It should be noted that references herein to the term
"distal" are to a direction away from an operator of the subject
invention, while references to the term "proximal" are to a
direction towards the operator of the subject invention.
Accordingly, when the terms "distal" and "proximal" are used herein
in the context of an assembly device that is being deployed by an
operator within a body, such as a human body, the term "distal"
refers to a location within the body that is further within the
body than a location that is "proximal" to the operator.
[0054] With reference to the drawings, FIG. 1 shows a perspective
view of a tubular structure for use as an exterior tubular
structure 10 in the assembly device of the subject invention. As
shown in FIG. 1, the exterior tubular structure 10 has a proximal
end 12, a distal end 14, and a lumen 16 that extends along the
length of the exterior tubular structure 10. The exterior tubular
structure 10 may have any suitable length and diameter. Desirably,
the exterior tubular structure 10 may have a uniform or
substantially uniform diameter throughout its entire length.
[0055] As shown in FIG. 1, the exterior tubular structure 10 may
have a marker 11 thereon. The marker 11 serves to indicate the
distal position of a stent 20 as it is inserted into the exterior
tubular structure 10 during assembly of the deployment device of
the subject invention.
[0056] The marker 11 may be made from any suitable marker material
known in the art. Suitable marker materials include any marker
material which is normally visible, such as ink and thread.
Suitable marker materials also include any radiopaque material such
as, for example, tantalum and barium sulfate. Desirably, the
exterior tubular structure 10 may be made from a transparent
extrusion material such that the stent 20 may be visible within the
exterior tubular structure 10 upon insertion of the stent 20
therein. For purposes of illustration, the exterior tubular
structure 10 is shown as a transparent extrusion material in FIGS.
1-3, 5-7, 12-13 and 24-25.
[0057] In some embodiments, an exterior tubular structure 10 may
have a handle 18 positioned on its proximal end 12, as further
shown, for example, in FIG. 1. Desirably, the handle 18 may be
designed to facilitate easy and gradual loading and constrainment
of a stent 20 within the exterior tubular structure 10. In some
embodiments, the handle 18 may have a funneled or conical section
18' and a straight portion 18''. For instance, the handle 18
depicted in FIG. 1 is funnel-shaped. With reference to FIG. 1, it
will be understood that handle 18 is positioned over at least a
portion of proximal end 12 of exterior tubular structure 10 such
that the proximal end 12 of exterior tubular structure 10 is
aligned with the distal end 27 of funneled or conical section 18'
of handle 18.
[0058] Desirably, funneled or conical section 18' of handle 18 is
designed to facilitate loading of stent 20 therein. For example, in
some embodiments, funneled or conical section 18' may be split to
facilitate loading of a stent 20 and then reassembled upon loading.
Moreover, in some embodiments, funneled or conical section 18' may
have a flat conical interior 23, as shown in FIG. 1. In other
embodiments, funneled or conical section 18' of handle 18 may have
a rounded interior 25, as shown in FIG. 21.
[0059] In some embodiments of the subject invention, a portion of a
stent 20 may be first inserted through the handle 18 of the
exterior tubular structure 10 and into the lumen 16 of the exterior
tubular structure 10 as shown in FIG. 1. The diameter of the
portion of the stent 20 may change to conform to the diameter of
the handle 18 and to the diameter of the exterior tubular structure
10 upon passage into the exterior tubular structure 10. By using a
handle 18 having a funneled or conical section 18', it may be
possible to allow the diameter of the stent 20 to decrease
gradually upon insertion through the handle 18 and into the
exterior tubular structure 10.
[0060] In some embodiments, the stent 20 may be only partially
inserted into the tubular structure 10 as shown in FIG. 1.
Desirably, in some embodiments, the stent 20 may be partially
inserted such that the distal end 32 of the stent 20 may be aligned
with the marker 11 of exterior tubular structure 10, as shown in
FIG. 1. As further shown in FIG. 1, the portion of the stent 20
that may be inserted into the tubular structure 10 may be in a
constrained state relative to the portion of the stent 20 that is
not inserted into the tubular structure 10 and relative to the
portion of the stent 20 that may be passed through the handle 18.
As used herein, the term "partially constrained stent" refers to a
stent 20 that may be partially inserted into an exterior tubular
structure 10 as shown in FIG. 1 such that at least a portion of the
stent may be in a constrained state.
[0061] In some embodiments, stent 20 may have a marker 11 thereon.
In particular, when exterior tubular structure 10 and handle 18 are
translucent or opaque as shown in FIGS. 24 and 25, stent 20 may
have a marker 11 thereon. Desirably, marker 11 is positioned on
distal end 32 of stent 20. In some embodiments, stent 20 is
partially inserted into an exterior tubular structure 10 having
base portion 18'' of handle 18 thereon until marker 11 on stent 20
is aligned with the proximal end 15 of the funneled or conical
section 18' of handle 18, as shown in FIG. 24, or with the proximal
end 12 of exterior tubular structure 10, as shown in FIG. 25.
[0062] In some embodiments, stent 20 may have a means 19 for
compressing the stent 20 thereon to facilitate loading of the stent
20 into the exterior tubular structure 10 and, more particularly,
into the handle 18 which may be positioned on exterior tubular
structure 10. Desirably, means 19 can be used alone or in
conjunction with manual manipulation to facilitate loading of the
stent 20.
[0063] In some embodiments, means 19 for compressing the stent 20
is a structure or device 19' which is capable of compressing the
distal end 32 of the stent 20, as shown in FIG. 22, which depicts a
stent 20 for use in accordance with the present invention having a
distal end 32' which is compressed by such a structure or device
19'. In particular, in such embodiments, structure or device 19'
may be, for example, a funnel introducer, as shown in FIG. 22. By
"funnel introducer" is meant a means or device (besides manual
manipulations) that may slightly compress the distal end 32 of the
stent 20 to conform the stent 20 to the conical or funneled section
18' of handle 18 and thereby facilitate entry of the stent 20
through handle 18 and into exterior tubular structure 10. As shown
in FIG. 22, distal end 32 of a stent 20 assumes a compressed state
32' as a result of the use of structure or device 19'.
[0064] In other embodiments, the means 19 for compressing the stent
20 may be any suitable packaging material 19'', as shown in FIG.
23, which is a perspective view of a stent 20 for use in accordance
with the present invention having a distal end 32 which is
compressed by such a packaging material 19''. In still other
embodiments, no means 19 for compressing the stent 20 is applied.
In such embodiments, manual manipulation may be employed to
compress the distal end 32 of stent 20 to facilitate entry of the
stent 20 into the exterior tubular structure 10 and, more
particularly, into handle 18, when stent 20 is inserted therein as
shown in FIG. 1. As shown in FIG. 23, distal end 32 of stent 20
assumes a compressed state 32' as a result of the use of the
packaging material 19''.
[0065] In some embodiments of the subject invention, the exterior
tubular structure 10 may be positioned over an inner tubular
structure or sheath 22 to constrain the stent 20 between the
exterior tubular structure 10 and the inner tubular structure 22 as
shown in FIG. 2, which is a perspective view of an exterior tubular
structure 10 and inner tubular structure 22 that are so positioned.
The exterior tubular structure 10 may be positioned over the inner
tubular structure 22 by pushing the exterior tubular structure 10
over the inner tubular structure 22. More particularly, in some
embodiments, the inner tubular structure 22 may be "backloaded"
into the exterior tubular structure 10 by pushing the distal end 26
of the inner tubular structure 22 through the handle 18 and into an
exterior tubular structure 10 having a stent 20 partially
constrained therein as described above with regard to FIG. 1. A
handle 23 may be positioned on the proximal end 24 of the inner
tubular structure 22 to facilitate loading of the inner tubular
structure 22 into the exterior tubular structure 10, as shown in
FIG. 2. As further shown in FIG. 2, the exterior tubular structure
10 has a lumen 16 extending therethrough.
[0066] The inner tubular structure 22 may be the "backbone" of the
delivery assembly devices and systems provided herein. Desirably,
the inner tubular structure 22 provides column strength,
pushability, and trackability when a delivery system of the subject
invention is pushed into an opening/tract of the human body (such
as the esophagus, an airway, a vessel or other body conduit). In
general, the inner tubular structure 22 may be made from an
extrusion material. Non-limiting examples of extrudable materials
which could be useful for outer 10 and inner 22 tubular structures
include any plastic or polymeric material. Desirably, the material
is somewhat hard but is a flexible plastic or polymeric
material.
[0067] The exterior tubular structure 10 may be transparent or
translucent, and is, desirably, substantially or partially
transparent or translucent. Furthermore, the tubular structure 10
may be constructed of any suitable biocompatible materials, such
as, but not limited to, polymers and polymeric materials, including
fillers such as metals, carbon fibers, glass fibers or ceramics.
Other useful materials for exterior tubular structure 10 include,
but are not limited to, polyethylene, polypropylene, polyvinyl
chloride, polytetrafluoroethylene, fluorinated ethylene propylene,
polystyrene, poly(ethylene terephthalate), polyurethane, silicone
rubbers, polyamides, polyimides, polycarbonates, and polyether
ether ketone. The exterior tubular structure may also include a
braided structure to improve mechanical properties such as tensile,
column strength and/or kink resistance. Desirably, exterior tubular
structure 10 is formed from polytetrafluoroethylene (PTFE).
[0068] The inner tubular structure 22 may be constructed of any
suitable biocompatible materials, such as, but not limited to,
polymers and polymeric materials, including fillers such as metals,
carbon fibers, glass fibers or ceramics. Other useful materials for
inner tubular structure 22 include, but are not limited to,
polyethylene, polypropylene, polyvinyl chloride, fluorinated
ethylene propylene, fluorinated ethylene propylene, polyvinyl
acetate, polystyrene, poly(ethylene terephthalate), naphthalene
dicarboxylate derivatives, such as polyethylene naphthalate,
polybutylene naphthalate, polytrimethylene naphthalate and
trimethylenediol naphthalate, polyurethane, polyurea, silicone
rubbers, polyamides, polyimides, polycarbonates, polyaldehydes,
polyether ether ketone, natural rubbers, polyester copolymers,
styrene-butadiene copolymers, polyethers, such as fully or
partially halogenated polyethers, and copolymers and combinations
thereof.
[0069] The inner tubular structure 22 may have any suitable length
and diameter, as long as the diameter of the inner tubular
structure 22 is less than the diameter of the exterior tubular
structure 10.
[0070] In some embodiments of the subject invention, a means 30 for
moving stent 20 is employed to cause movement of stent 20 within
the exterior tubular structure 10 upon insertion of the inner
tubular structure 22 therein, as shown in FIG. 2, which shows a
stent 20 which has partially been moved within exterior tubular
structure 10 as a result of the employment of a means 30 for moving
stent 20. In particular, means 30 for moving stent 20 causes
movement of the stent 20 within the exterior tubular structure 10
upon insertion of the inner tubular structure 22 therein.
[0071] In some embodiments, the means 30 for moving stent 20 moves
stent 20 by engaging stent 20 such as by becoming coupled to stent
20. In other embodiments, means 30 for moving stent 20 moves stent
20 by pushing the stent 20 into the desired position.
[0072] In some embodiments, a guide wire 13 may be positioned
within the inner tubular structure 22 as shown in FIG. 2.
[0073] Desirably, means 30 for moving stent 20 causes the stent 20
and the inner tubular structure 22 to move concomitantly within the
exterior tubular structure 10. In particular, in some embodiments,
when the means 30 for moving stent 20 comes into contact with the
stent 20 shown in FIG. 1, the means 30 desirably anchors the stent
20 to the inner tubular structure 22, i.e., locks the stent 20 into
position on the inner tubular structure 22, such that distal
movement of the inner tubular structure 22 causes the stent 20 to
slide distally within the exterior tubular structure 10 in the
direction of the arrow 29 shown in FIG. 2.
[0074] In some embodiments, the means 30 for moving stent 20 may be
a stent-engaging member that is a separate and distinct structure
from inner tubular structure 22. When such a stent-engaging member
is used, the stent-engaging member may be capable of being
dis-engagingly attached to inner tubular structure 22. For example,
the stent-engaging member may be an annular protuberance 31 such as
an o-ring that is capable of being slipped onto the inner tubular
structure 22, as shown in the perspective view of FIG. 26. Such a
stent-engaging member may be attached to the inner tubular
structure 22 by any suitable method known in the art. For example,
the stent-engaging member may be molded onto the inner tubular
structure 22.
[0075] In other embodiments, the means 30 for moving stent 20 is a
stent-engaging portion that is part of the inner tubular structure
22 itself. When the means 30 for engaging stent 20 is a part of the
inner tubular structure 22, the means 30 may be, for example, a
flap 57 which is cut into inner tubular structure 22, as shown in
FIG. 27. In other embodiments, when the means 30 for moving stent
20 is a part of the inner tubular structure 22, the means 30 may be
a pattern 53 or at least one divot 55 in structure 22, as shown in
FIGS. 28 and 32, respectively. In yet other embodiments, when the
means 30 for moving stent 20 is a part of the inner tubular
structure 22, the means 30 may be a compressive and/or a
tacky/sticky layer 35, as shown in FIG. 29. Although layer 35 is
shown on only a portion of inner tubular structure 22 in FIG. 29,
it will be understood that layer 35 may span the entire length of
inner tubular structure 22. In still other embodiments, when the
means 30 for moving stent 20 is a part of the inner tubular
structure 22, the means 30 may be a bump 51, as shown in FIG. 30,
or an annular ridge 45, as shown in FIG. 31. Although not shown, it
will be understood that inner tubular structure may have more than
one of any of the aforementioned means 30 for moving stent 20
thereon and any combination thereof.
[0076] In some embodiments, when it is desired to re-constrain the
stent 20 after partial deployment within the exterior tubular
structure 10, it may be especially useful to hold the stent 20 in
position on the inner tubular structure 22 by means of the
dis-engagable means 30 for moving the stent 20 for the purpose of
moving the stent 20 into the loaded position such that the delivery
system may be subsequently delivered into the body lumen and the
stent 20 deployed thereafter. In such embodiments, the exterior
tubular structure 10 may be pushed back over the stent 20 without
the stent 20 sliding along with the exterior tubular structure
10.
[0077] FIG. 3 shows a stent delivery device 47 of the present
invention in its final form before use. As shown in the perspective
view of FIG. 3, the distal end 26 of the inner tubular structure 22
may be aligned with the distal end 14 of the exterior tubular
structure 10. When the distal end 26 of the inner tubular structure
22 is aligned with the distal end 14 of the exterior tubular
structure 10, the distal end 32 of the stent 20 also is desirably
aligned with the distal end 14 of the exterior tubular structure
10, as further shown in FIG. 3. In such embodiments, the stent 20
may be fully constrained within the exterior tubular structure 10,
i.e., the stent 20 may be fully covered by the exterior tubular
structure 10 such that it is in a constrained state relative to its
free state.
[0078] As shown in FIG. 3, the delivery system of the present
invention may include a tip 34 which is attached to the distal end
26 of the inner tubular structure 22 as shown in FIG. 3. Tip 34
desirably imparts a "softer," more flexible profile to the delivery
system, thus improving the assembly device profile when the
assembly device is pushed and tracked through tortuous, narrow,
luminal anatomy.
[0079] Tip 34 shown in FIG. 3 may be assembled onto the distal end
26 of the inner tubular structure 22 either prior to the insertion
of the inner tubular structure 22 into the exterior tubular
structure 10 or after the insertion of the inner tubular structure
22 into the exterior tubular structure 10.
[0080] In embodiments where the tip 34 is preassembled on the inner
tubular structure 22, tip 34 may be compressible and desirably
capable of expansion. In particular, when tip 34 is preassembled on
inner tubular structure 22, tip 34 may assume a reduced profile 34'
when the inner tubular structure 22 having tip 34 attached thereto
is passed through a partially loaded stent 20 prior to the means 30
for moving stent 20 engaging the stent 20, as shown in the
perspective view in FIG. 5. Desirably, the tip 34 may be designed
to minimize the amount of friction that occurs between the stent 20
and the tip 34 upon insertion of the inner tubular structure 22
within the stent 20.
[0081] Tip 34 then may assume an expanded profile 34'' after the
means 30 for moving stent 20 engages the stent 20, as shown in the
perspective view in FIG. 6. In some embodiments, at least a portion
of a tip 34'' having an expanded profile may come into contact with
at least a portion of the exterior tubular structure 10 during
passage therein as shown in FIG. 6. In yet other embodiments, when
the tip 34 is preassembled onto the inner tubular structure 22, the
tip 34 may maintain a reduced profile 34' until the tip 34 is
pushed outside of the exterior tubular structure 10, at which point
the tip assumes an expanded profile 34'' as shown in the
perspective view in FIG. 7, which shows a stent delivery device 49
of the present invention which is ready for deployment in a bodily
lumen. In such embodiments, the exterior tubular structure 10
constrains the tip 34 while the same is being "back-loaded" into
the exterior tubular structure 10.
[0082] As noted above, in some embodiments, tip 34 may be assembled
onto inner tubular structure 22 after insertion of the inner
tubular structure 22 into the exterior tubular structure 10. In
such embodiments, the inner tubular structure 22 is inserted into
exterior tubular structure 10 such that the distal end 26 of the
inner tubular structure 22 is aligned with the distal end 14 of the
exterior tubular structure 10. Thereafter, tip 34 is attached to
the inner tubular structure 22 to form the stent delivery system 47
of the present invention as shown in FIG. 3.
[0083] The tip 34 may have any suitable design and may be attached
to the inner tubular structure 22 using any suitable method. For
example, tip 34 and inner tubular structure 22, as shown in FIGS.
5-7, may be attached together by means of, for example, a snap-fit,
clip or screw-on assembly method and any other suitable attachment
means known in the art.
[0084] Another method of attaching tip 34 to inner tubular
structure 22 involves a "push-on lock" that interacts with the
distal end 26 of the inner tubular structure 22, as shown in FIGS.
8a-8e. In particular, as shown in the perspective view in FIG. 8a,
the tip 34 may have a portion 37 that interlocks with a portion 43
of an inner tubular structure 22 upon insertion therein, as shown
in the perspective view in FIG. 8b. Alternatively, the tip 34 may
have a portion 39 as shown in the perspective view in FIG. 8c into
which an inner tubular structure 22 can be inserted. An inner
tubular structure 22 suitable for insertion into such a tip 34 is
shown in FIG. 8d and may have a portion 40 that interlocks with the
portion 39 of the tip 34 shown in FIG. 8c to lock the tip 34 and
inner tubular structure 22 together as shown in FIG. 8e. A tip 34
as shown in FIG. 8a may desirably be attached to an inner tubular
structure 22 as shown in FIG. 8b as a final step in the assembly of
the stent-delivery systems disclosed herein.
[0085] In some embodiments, a tip 34 as shown in FIG. 8a may be
threaded to the distal end 26 of the inner tubular structure 22
shown in FIG. 8b. A tip 34 and an inner tubular structure 22
attached by means of a thread 41 is shown in the perspective view
in FIG. 9. Affixing a tip 34 to an inner tubular structure 22 in
such a manner may desirably be the final step in the assembly of
the stent-delivery systems disclosed herein.
[0086] Another method for attaching a tip 34 to an inner tubular
structure 22 involves a clip-retaining method. In this method, an
inner tubular structure 22 having a slot 46 therein, as shown in
the perspective view in FIG. 10b, is inserted into a tip 34 having
a slot 44 therein, as shown in the perspective view in FIG. 10a.
Upon insertion of the inner tubular structure 22 into the tip 34,
the slot 46 of the inner tubular structure 22 aligns with the slot
44 of the tip 34. A locking clip 42 may then be placed into the
slot 46 of the inner tubular structure and the slot 44 of the tip
34 to affix the tip 34 to the inner tubular structure 22 as shown
in the perspective view in FIG. 10c. A tip 34, as shown in FIG.
10a, may desirably be attached to an inner tubular structure 22, as
shown in FIG. 10b, as a final step in the assembly of the
stent-delivery systems disclosed herein.
[0087] In yet another method, an inner tubular structure 22 may be
inserted into a tip 34 having collapsible hinges or fins 48, as
shown in the perspective view in FIG. 11a. Desirably, the
collapsible hinges or fins 48 flex to allow the tip 34 to be loaded
into an exterior tubular structure 10 of the subject invention as
shown in the perspective view in FIG. 11b using the method
described above with regard to FIGS. 1 and 2. After the tip 34
emerges from the exterior tubular structure 10, the collapsible
hinges or fins 48 may desirably open up to prevent the tip 34 from
being retracted into the exterior tubular structure 10, as shown in
the perspective view in FIG. 11c.
[0088] In some embodiments, tip 34 may be attached to inner tubular
structure 22 by means of an adhesive. Additionally, or in the
alternative, the tip 34 may be molded over the inner tubular
structure 22. Desirably, the tip 34 and inner tubular structure 22
shown in FIGS. 11 a-11 c may be attached by either or both of these
methods.
[0089] In still other embodiments, tip 34 may be attached to inner
tubular structure 22 by means of one or more structures which are
inherent to tip 34. In particular, tip 34 may include a clip or
lock 50 on the inner surface 52 of tip 34, as shown in the
cross-sectional view of tip 34 shown in FIG. 4a. In such
embodiments, inner tubular structure 22 may include a groove or
indentation 54, as shown in FIG. 4b, which is capable of engaging
clip or lock 50 to attach inner tubular structure 22 to clip or
lock 50, as shown in FIG. 4c. Although not shown, it will be
understood that tip 34 may include a groove or indentation 54 on
its inner surface 52 and inner tubular structure 22 may include a
clip or lock 50 which is capable of engaging the groove or
indentation 54 on the inner surface 52 of tip 34 to attach tip 34
to inner tubular structure 22.
[0090] In other embodiments, tip 34 may include a bump or hole on
its inner surface 52, and inner tubular structure 22 may contain
the other of said bump or hole. Bump or hole on said inner tubular
structure 22 may then engage with the other of said bump or hole
which is on the inside surface of tip 34 to "click" inner tubular
structure 22 into place in the inside of tip 34.
[0091] With reference to FIG. 33a, which is a cross-sectional view
of a tip 34, that figure illustrates tip 34 having a hole 61 on its
inner surface 52. In such embodiments, inner tubular structure 22
may include a bump 56, as shown in FIG. 33b, which is capable of
engaging hole 61 of tip 34, as shown in FIG. 33c to attach tip 34
to inner tubular structure 22.
[0092] With reference to FIG. 34a, which is a cross-sectional view
of a tip 34, that figure illustrates tip 34 having a bump 56' on
its inner surface 52. In such embodiments, inner tubular structure
22 may include a hole 61', as shown in FIG. 34b, which is capable
of engaging bump 56' to attach tip 34 to inner tubular structure
22, as shown in FIG. 34c.
[0093] In yet other embodiments the inside of tip 34 may include a
key or slot and the inner tubular structure 22 may include the
other of said key or slot. With reference to FIG. 35a, which is a
cross-sectional view of a tip 34, that figure illustrates tip 34
having a slot 58 within the inner surface 52 of tip 34. In such
embodiments, inner tubular structure 22 may include a key 60, as
shown in FIG. 35b, which is capable of engaging slot 58 to attach
tip 34 to inner tubular structure 22, as shown in FIG. 35c.
Although not shown, it will be understood that tip 34 may include a
key 60 on its inner surface 52 and inner tubular structure 22 may
include a slot 58 which is capable of engaging the key 60 on the
inner surface 52 of tip 34 to attach tip 34 to inner tubular
structure 22.
[0094] In yet other embodiments, inner tubular structure 22 may be
attached to tip 34 by means of barbs. With reference to FIG. 36a,
which is a cross-sectional view of a tip 34, that figure
illustrates tip 34 having barbs 62 on the inner surface 52 of tip
34. In such embodiments, inner tubular structure 22 also may
include barbs 62', as shown in FIG. 36b, which are capable of
engaging barbs 62 on inner surface 52 of tip 34 to attach tip 34 to
inner tubular structure 22 as shown in FIG. 36c.
[0095] In still other embodiments, inner tubular structure 22 may
be attached to tip 34 by means of ribs. With reference to FIG. 37a,
which is a cross-sectional view of a tip 34, that figure
illustrates tip 34 having ribs 64 on its inner surface 52. In such
embodiments, inner tubular structure 22 may include indentations
66, as shown in FIG. 37b, which are capable of engaging ribs 64 on
inner surface 52 of tip 34 to attach tip 34 to inner tubular
structure 22 as shown in FIG. 37c. Although not shown, tip 34 may
include indentations 66 on its inner surface 52 and inner tubular
structure 22 may include ribs 64 which are capable of engaging
indentations 66 on the inner surface 52 of inner tubular structure
22 to attach tip 34 to inner tubular structure 22.
[0096] In yet other embodiments, inner tubular structure 22 may be
attached to tip 34 by means of hooks and loops (such as Velcro). In
such embodiments, when inner tubular structure 22 includes one of
said hooks and loops, tip 34 includes the other of said hooks and
loops.
[0097] With reference to FIG. 38a, which is a cross-sectional view
of a tip 34, that figure illustrates tip 34 having loops 68 on its
inner surface 52. In such embodiments, inner tubular structure 22
may include hooks 70, as shown in FIG. 38b, which are capable of
engaging loops 68 on inner surface 52 of tip 34 to attach tip 34 to
inner tubular structure 22, as shown in FIG. 38c.
[0098] With reference to FIG. 39a, which is a cross-sectional view
of a tip 34, that figure illustrates tip 34 having hooks 70' on its
inner surface 52. In such embodiments, inner tubular structure 22
may include loops 68', as shown in FIG. 39b, which are capable of
engaging hooks 70' to attach tip 34 to inner tubular structure 22,
as shown in FIG. 39c.
[0099] Desirably, in some embodiments of the subject invention, two
or more means 30, 30' for moving a stent 20 may be used in the
stent delivery devices. Desirably, one means 30 for moving a stent
20 may be positioned on the inner tubular structure 22 such that it
becomes attached to the proximal end 33 of the stent 20 as shown in
FIG. 12, which is a perspective view of an exterior tubular
structure 10 having an inner tubular structure 22 and stent 20
inserted therein in the manner described above with regard to FIGS.
1 and 2. The other means 30' for moving a stent 20 may be
positioned on the inner tubular structure 22 such that it becomes
coupled to the distal end 32 of the stent 20, as further shown in
FIG. 12. With reference to FIG. 12, it will be understood that
inner tubular structure 22 having handle 23 thereon is used to load
stent 20 through the handle 18 of outer tubular structure 10 as
described above with regard to FIGS. 1 and 2. Means 30, 30' for
moving stent 20 then move stent 20 to the distal end 14 of the
exterior tubular structure 10 upon insertion of the inner tubular
structure 22 within outer tubular structure 10 to form a stent
delivery device 72 as shown in FIG. 12 which is ready for
deployment in the body.
[0100] When two or more means 30, 30' for moving a stent 20 are
used, the means 30' that may engage the distal end 32 of the stent
20 desirably allows for early catching and sliding of the
constrained stent 20, while the means 30 that engages the proximal
end 33 of the stent 20 desirably allows for reconstrainment of the
stent 20 after partial deployment of the stent 20. Desirably, the
stent 20 may be partially deployed such that the stent 20 may have
a length that is up to 95% of the length of the stent 20 in its
free, non-constrained state. A stent 20 that may be engaged to an
inner tubular structure 22 by means of two or more means for moving
stent 30, 30' further decreases the risk of stent slippage.
[0101] The means 30, 30' for moving stent 20 may be any suitable
structures useful for that purpose and may have any suitable
design. For example, the means 30 and/or 30' may be a stent holder
or anchor component, as shown in FIG. 12. In some embodiments, the
means 30 and/or 30' may be a flat holder that increases friction
locally between the inner tubular structure 22 and the exterior
tubular structure 10, as shown in FIG. 13. In some embodiments,
means 30 and/or 30' may be an o-ring. Moreover, or in the
alternative, the structure 30 and/or 30' may have fins or teeth or
other protrusions thereon to "catch" the stent 20 and hold it in
place.
[0102] In such embodiments where two or more means 30, 30' for
moving stent 20 are used, the structures 30, 30' may be the same or
different. In particular, means 30 may have one design while
structure 30' has a different design. For example, in some
embodiments means 30 may be protrusions, while means 30' may be an
o-ring.
[0103] In some embodiments of the subject invention, the inner
tubular structure 22 may include a proximal portion 22' which is
larger than a distal diameter portion 22'', as shown in FIG. 13,
which is a perspective view of an exterior tubular structure 10
having an inner tubular structure 22 and stent 20 inserted therein
in the manner described above with regard to FIGS. 1 and 2.
Desirably, the proximal portion 22' will have an outer diameter
that is within about 0.1 to 0.5 mm of the inner diameter of the
exterior tubular structure 10. Moreover, the diameter of the distal
diameter portion 22'' of the inner tubular structure 22 is
desirably 2-3 mm less than the diameter of the proximal diameter
portion 22' of the inner tubular structure 22. Desirably, the
distal diameter portion 22'' engages the stent to advance the stent
forward toward the distal end of the stent delivery system.
[0104] The stent 20 of the stent delivery assemblies illustrated
herein may be deployed or loaded by pulling on the handle 18 of the
exterior tubular structure 10 while maintaining the inner tubular
structure 22 in place by grasping the handle 23 of the inner
tubular structure. During stent deployment in the body, retracting
the exterior tubular structure 10 may allow the stent 20 to
release.
[0105] Any suitable stent may be used in the stent delivery systems
of the present invention. In particular, various stent types and
stent constructions may be employed in the invention. Among the
various stents useful include, without limitation, self-expanding
stents. The stents may be capable of radially contracting as well
and in this sense can best be described as radially distensible or
deformable. Self-expanding stents include those that have a
spring-like action which causes the stent to radially expand, or
stents which expand due to the memory properties of the stent
material for a particular configuration at a certain temperature.
Nitinol is one material which has the ability to perform well while
both in spring-like mode, as well as in a memory mode based on
temperature. Other materials are of course contemplated, such as
stainless steel, platinum, gold, titanium and other biocompatible
metals, as well as polymeric stents, including biodegradable and
bioabsorbable stents. The configuration of the stent may also be
chosen from a host of geometries. For example, wire stents can be
fastened into a continuous helical pattern, with or without a
wave-like or zig-zag in the wire, to form a radially deformable
stent. Individual rings or circular members can be linked together
such as by struts, sutures, welding or interlacing or locking of
the rings to form a tubular stent. Tubular stents useful in the
invention also include those formed by etching or cutting a pattern
from a tube. Such stents are often referred to as slotted stents.
Furthermore, stents may be formed by etching a pattern into a
material or mold and depositing stent material in the pattern, such
as by chemical vapor deposition or the like. Examples of various
stent configurations are shown in U.S. Pat. No. 4,503,569 to
Dotter, U.S. Pat. No. 4,856,561 to Hillstead, U.S. Pat. No.
4,580,568 to Gianturco, U.S. Pat. No. 4,732,152 to Wallsten, and
U.S. Pat. No. 5,876,448 to Thompson, all of whose contents are
incorporated herein by reference. Braided, knitted, and laser-cut
stents are particularly useful.
[0106] As depicted in FIG. 40, one embodiment of the present
invention applies the method and system of the present invention to
a braided stent 20. FIG. 40 is an exploded or enlarged view of the
stent 20 to depict the braiding of the stent filaments 75. As used
herein the term braiding and its variants refer to the diagonal
intersection of elongate filaments 75 so that each filament passes
alternately over and under one or more of the other filaments,
which is commonly referred to as an intersection repeat pattern.
Useful braiding patterns include, but are not limited to, a diamond
braid having a 1/1 intersection repeat pattern, a regular braid
having a 2/2 intersection repeat pattern or a hercules braid having
a 3/3 intersection repeat pattern. The passing of the filaments
under and over one and the other results in slidable filament
crossings that are not interlooped or otherwise mechanically
engaged or constrained.
[0107] As described above, various stent types and stent
constructions may be employed in the invention as the stent 20, and
the invention can be constructed to accommodate stents of various
sizes and configurations. Non-limiting examples of suitable stent
geometries for stent 20 are illustrated in FIGS. 14-20. In
particular, stent 20 may be a wire stent 74. As shown in FIG. 14,
wire stent 74 is a hollow tubular structure formed from wire strand
76 or multiple wire strands. Wire stent 74 may be formed by, for
example, braiding or spinning wire strand(s) 76 over a mandrel (not
shown). Wire stent 74 is capable of being radially compressed and
longitudinally extended for implantation into a bodily lumen. The
degree of elongation depends upon the structure and materials of
the wire stent 74 and can be quite varied, for example, about 5% to
about 200% of the length of wire stent 74. The diameter of wire
stent 74 may also become several times smaller as it elongates.
[0108] Unitary stent structures may be obtained by braiding and/or
filament winding stent wires to obtain complex stent geometries,
including complex stent geometries, including complex bifurcated
stents. Alternatively, stent components of different sizes and/or
geometries may be mechanically secured by welding or suturing.
Additional details of wire stents of complex geometry are described
in U.S. Pat. Nos. 6,325,822 and 6,585,758, the contents of which
are incorporated herein by reference.
[0109] Stent 20 may have one or more atraumatic open end(s). As
used herein, the phrase "atraumatic end," and it variants, refers
to a terminal end of a stent which is free of sharp wire ends or
other sharp projections or deformities which may cause trauma when
implanted into a bodily lumen. In particular, the wires of stent 20
may be braided so as to produce an atraumatic end. For example,
certain wires of stent 20 may be extended and looped back to
provide an atraumatic end having, for example, no sharp or
traumatically pointed bends, no sharp wire ends, and no other
traumatically sharp projections or deformities or the like.
[0110] In some embodiments, as depicted in FIG. 15, braided stent
76 is desirably an atraumatic stent having no sharp terminating
members at one or both of the opposed open ends 78, 80. In
particular, such a stent desirably has atraumatic ends, i.e., ends
which are free or substantially free of loose wire ends or of other
sharp projections. The elongate stent wires terminating at open end
80 are mated to form closed loops 82 and adjacently mated wires are
secured to one and the other by mechanical means, such as welds 84.
The positioning of adjacently mated wires to form closed-loop end
designs is further described in U.S. Patent Application Publication
Nos. 2005/0049682 A1 and 2006/0116752 A1, the contents of which are
incorporated herein by reference. Desirably, the elongate wires
terminating at open end 80 are in a cathedral type arch or loop
configuration. Further details of the cathedral type of arch or
closed-loop configuration may be found in U.S. Patent Application
Publication No. 2005/0256563 A1, the contents of which are
incorporated herein by reference. The stent wires at the opposed
open end 78 may also be free of any sharp terminating points by,
for example, commencing braiding of the wires under tension over a
pin (not shown) so that the wire ends terminate just at the end 80,
where the wire ends may be looped and welded thereat.
[0111] A zig-zag wire stent 86 may also be useful as stent 20. Wire
strand 88 may be arranged in what can be described as a multiple of
"Z" or "zig-zag" patterns to form a hollow tubular stent. The
different zig-zag patterns may optionally be connected by
connecting member 90. Further, zig-zag wire stent 86 is not limited
to a series of concentric loops as depicted in FIG. 16, but may be
suitably formed by helically winding of the "zig-zag" pattern over
a mandrel (not shown). For example, as depicted in FIG. 17, zig-zag
stent 92 is formed by helically winding at least one stent wire 94
with no interconnections between the helically wound undulating
portions. The wire ends (not shown) may be looped and welded to
provide no sharp wire ends at the ends of the stent.
[0112] A slotted stent 96 may also be useful as stent 20. As
depicted in FIG. 18, slotted stent 96 is suitably configured for
implantation into a bodily lumen (not shown).
[0113] Other useful stents capable of radial expansion are depicted
in FIGS. 19 and 20. As depicted in FIG. 19, stent 98 is a helical
coil which is capable of achieving a radially expanded state (not
shown). Stent 100, as depicted in FIG. 20, has an elongate
pre-helically coiled configuration as shown by the waves of
non-overlapping undulating windings. These helically coiled or
pre-helically stents, commonly referred to as nested stents, are
also useful with the practice of one embodiment of the
invention.
[0114] Further, as depicted in FIG. 44, the stent 20 may have a
straight or substantially straight longitudinal portion 102. The
present invention, however, is not so limited. For example, the
stent 20 may have a varied diameter, such as a flaring or tapering,
along a portion or portion of its longitudinal expanse. One
non-limiting example of a varied diameter stent 20 is depicted in
FIG. 45. The stent 20 of FIG. 45 may include a longitudinal length
102 and one or two flared ends 104. As depicted in FIG. 45, the
flared ends 104 are enlarged flared ends having a diameter greater
than the diameter of the longitudinal portion 102 of the stent 20.
The stent 20, however, is not so limited, and for example the
flared ends 104, individually or in combination, may have a smaller
diameter than the diameter of the longitudinal portion 102 of the
stent 20. Further, the stent 20 may be repositionable, removable
and/or reconstrainable, and/or may include multiple interconnected
or non-interconnected stents. For example, the stent 20 may include
a loop or element, such as a suture loop or element, a polymeric
loop or element, metallic loop or element, and combinations thereof
which may be accessible to a user or practitioner, for example by
the use of forceps, to reposition, remove and/or reconstrain the
stent 20 after it has been delivered, partially or totally, to a
bodily lumen. Moreover, a loop or element may be integrally formed
as part of the stent 20. Further details of useful repositioning,
removing and/or reconstraining loops or elements may be found in
U.S. patent application Ser. No. 11/341,540, filed Jan. 27, 2006,
and entitled "Stent Retrieval Member And Devices And Methods For
Retrieving Or Repositioning A Stent", which published as U.S.
Patent Application Publication No. 2006/0190075 A1, and in U.S.
patent application Ser. No. 11/432,065, filed May 11, 2006, and
entitled "Integrated Stent Respostioning And Retrieval Loop", which
published as U.S. Patent Application Publication No. 2006/0276887
A1, the contents of both of which are incorporated herein by
reference.
[0115] In some embodiments, stent may be formed of a metal braid
formed of a flat wire. In such embodiments, the flat wire may have
a width of between 0.001 inches (0.025 mm) and 0.005 inches (0.13
mm) and a thickness of about 0.001 inches (0.025 mm).
[0116] The stent may be coated with a polymeric material. For
example, the stent wires may be partially or fully covered with a
biologically active material which is elutably disposed with the
polymeric material. Further, the polymeric coating may extend over
or through the interstitial spaces between the stent wires so as to
provide a hollow tubular liner or cover over the interior or the
exterior surface of the stent, thereby providing a stent-graft
device. The polymeric material may be selected from the group
consisting of polyester, polypropylene, polyethylene, polyurethane,
polynaphthalene, polytetrafluoroethylene, expanded
polytetrafluoroethylene, silicone, and combinations thereof. The
covering may be in the form of a tubular structure. The silicone
covering may be suitably formed by dip coating the stent. Details
of such dip coating may be found in U.S. Pat. No. 5,875,448, the
content of which is incorporated herein by reference. The present
invention is not limited to forming the silicone film by dip
coating, and other techniques, such as spraying, may suitably be
used. After applying the silicone coating or film to the stent, the
silicone may be cured. Desirably, the curing is low temperature
curing, for example from about room temperature to about 90.degree.
C. for a short period of time, for example from about 10 minutes or
more to about 16 hours. The cured silicone covering may also be
sterilized by electronic beam radiation, gamma radiation, ethylene
oxide treatment and the like. Further details of the curing and/or
sterilization techniques may be found in U.S. Pat. No. 6,099,562,
the content of which is incorporated herein by reference. Argon
plasma treatment of the cured silicone may also be used. Argon
plasma treatment of the cured silicone modifies the surface to the
cured silicone to, among other things, make the surface less
sticky. The invention, however, is not limited to stent-graft
devices having polymeric coatings. The graft portion may suitably
be formed from polymeric films, polymeric tapes, polymeric tubes,
polymeric sheets and textile materials. Textile material may be
woven, knitted, braided and/or filament wound to provide a suitable
graft. Various biocompatible polymeric materials may be used as
textile materials to form the textile structures, including
polyethylene terephthalate (PET), naphthalene dicarboxylate
derivatives such as polyethylene naphthalate, polybutylene
naphthalate, polytrimethylene naphthalate, trimethylenediol
naphthalate, ePTFE, natural silk, polyethylene and polypropylene,
among others. Moreover, textile materials and stent materials may
be co-formed, for example co-braided, to form a stent-graft
device.
[0117] In some embodiments, stent 20 is a joined or welded stent.
In such a stent, elongate wires terminating at an open end of the
stent are mated, and adjacently mated wires are secured by welds or
other suitable means. For example, the wires may be welded together
through use of a welding material or the wires may be fused
together without the use of a welding material by means of heating
and/or melting. Furthermore, the wires may be mechanically joined,
such as, for example, through the use of small-sized or
micro-fabricated clamps, crimpable tubes, hypotubes, and the
like.
[0118] Although the stent may be formed of metals, plastics or
other materials, it is preferred that a biocompatible material or
construction is used. In particular, the wires or filaments of
stents useful in the present invention may be made from a
biocompatible material or biocompatible materials. Useful
biocompatible materials include, but are not limited to,
biocompatible metals, biocompatible alloys, biocompatible polymeric
materials, including synthetic biocompatible polymeric materials
and bioabsorbable or biodegradable polymeric materials, materials
made from or derived from natural sources and combinations thereof.
Desirably, the wires are biocompatible metals or alloys made from,
for example, nitinol, stainless steel, a cobalt-based alloy such as
Elgiloy, platinum, gold, titanium, tantalum, niobium, polymeric
materials, and combinations thereof. Useful synthetic biocompatible
polymeric materials include, but are not limited to, polyesters,
including polyethylene terephthalate (PET) polyesters,
polypropylenes, polyethylenes, polyurethanes, polyolefins,
polyvinyls, polymethylacetates, polyamides, naphthalene
dicarboxylene derivatives, silks, and polytetrafluoroethylene. The
polymeric materials may further include a metallic, glass, ceramic
or carbon constituent or fiber. Useful and non-limiting examples of
bioabsorbable or biodegradable polymeric materials include
poly(L-lactide) (PLLA), poly(D,L-lactide) (PLA), poly(glycolide)
(PGA), poly(L-lactide-co-D,L-lactide) (PLLA/PLA),
poly(L-lactide-co-glycolide) (PLLA/PGA),
poly(D,L-lactide-co-glycolide) (PLA/PGA),
poly(glycolide-co-trimethylene carbonate) (PGA/PTMC), polydioxanone
(PDS), polycaprolactone (PCL), polyhydroxybutyrate (PHBT),
poly(phosphazene), poly(D,L-lactide-co-caprolactone) (PLA/PCL),
poly(glycolide-co-caprolactone) (PGA/PCL), poly(phosphate ester),
and the like. Further, stent 20 may include materials made from or
derived from natural sources, such as, but not limited to,
collagen, elastin, glycosaminoglycan, fibronectin and laminin,
keratin, alginate, combinations thereof and the like.
[0119] Wires made from polymeric materials also may include
radiopaque materials, such as metallic-based powders or
ceramic-based powders, particulates or pastes, which may be
incorporated into the polymeric material. For example, the
radiopaque material may be blended with the polymer composition
from which the polymeric wire is formed, and subsequently fashioned
into the stent. Alternatively, the radiopaque material may be
applied to the surface of the metal or polymer stent. In either
embodiment, various radiopaque materials and their salts and
derivatives may be used including, without limitation, bismuth,
barium and its salts such as barium sulfate, tantalum, tungsten,
gold, platinum and titanium, to name a few. Additional useful
radiopaque materials may be found in U.S. Pat. No. 6,626,936, which
is herein incorporated in its entirety by reference. Metallic
complexes useful as radiopaque materials also are contemplated.
[0120] Stent 20 may be selectively made radiopaque at desired areas
along the wire or may be made fully radiopaque, depending on the
desired end-product and application. Furthermore, the wires of
stent 20 may have an inner core of tantalum, gold, platinum, or
iridium, or a combination thereof, and an outer member or layer of
nitinol to provide a composite wire for improved radiopacity or
visibility.
[0121] Alternatively, the stent 20 may also have improved external
imaging under magnetic resonance imaging (MM) and/or ultrasonic
visualization techniques. MRI is produced by complex interactions
of magnetic and radio frequency fields. Materials for enhancing
Mill visibility include, but are not to be limited to, metal
particles of gadolinium, iron, cobalt, nickel, dysprosium,
dysprosium oxide, platinum, palladium, cobalt-based alloys,
iron-based alloys, stainless steels, or other paramagnetic or
ferromagnetic metals, gadolinium salts, gadolinium complexes,
gadopentetate dimeglumine, compounds of copper, nickel, manganese,
chromium, dysprosium and gadolinium. To enhance the visibility
under ultrasonic visualization the stent 20 of the present
invention may include ultrasound resonant material, such as but not
limited to gold. Other features, which may be included with the
stent 20 of the present invention, include radiopaque markers;
surface modification for ultrasound, cell growth or therapeutic
agent delivery; varying stiffness of the stent or stent components;
varying geometry, such as tapering, flaring, bifurcation and the
like; varying material; varying geometry of stent components, for
example tapered stent filaments; and the like.
[0122] Desirably, the wires are made from nitinol, or a composite
wire having a central core of platinum and an outer layer of
nitinol. Desirably, the inner core of platinum represents about at
least 10% of the wire based on the overall cross-sectional
percentage. Moreover, the nitinol desirably has not been treated
for shape memory such as by heating, shaping and cooling the
nitinol at its martensitic and austenitic phases. Further details
of suitable composite wires may be found in U.S. Patent Application
Publication 2002/0035396 A1, the contents of which are incorporated
herein by reference.
[0123] The wires of stent 20 may have any suitable diameter.
Desirably, the wires are relatively thin and have a diameter of
about 0.01 to 0.02 inches.
[0124] Moreover, stent 20 may contain any suitable number of wires.
Desirably, an even number of wires is used. For example, in some
embodiments, stent 20 may contain from about 10 to about 36 wires.
Furthermore, stent 20 also may include apertures and/or
discontinuities (not shown) along portions of the stent wall.
[0125] The stent 20, inner tubular structure 22, and/or exterior
tubular structure 10 may have coverings, films, coatings, and the
like disposed over, under or throughout or embedding the stent 20.
Any suitable covering, film, coating, and the like may be used in
combination with the stent 20, the inner tubular structure 22,
and/or the exterior tubular structure 10. In particular, the stent
20 may be fully, substantially or partially covered with such a
covering, film, coating, and the like on an external and/or
internal surface of the stent 20. The covering may be, for example,
a graft covering in the form of a hollow, tubular graft
structure.
[0126] For example, as depicted in FIG. 41, the stent 20 may
include a covering 106, desirably a polymeric covering, disposed
over the longitudinal length or a portion of the longitudinal
length of the stent 20. Further, as depicted in FIG. 42, the stent
20 may include a liner 108, desirably a polymeric liner, disposed
within the longitudinal length or a portion of the longitudinal
length of the stent 20. Moreover, as depicted in FIG. 43, the stent
20 may include both a covering 106 and a liner 108, desirably a
polymeric covering and liner which include the same or different
polymeric materials, disposed over and within the longitudinal
length or a portion of the longitudinal length of the stent 20. The
covering and the liner of FIG. 43 may be a unitary film or coating
that embeds or partially embeds the stent 20. The covering 106
and/or the liner 108 may be in the form of a tubular structure, for
example composed of polymeric material and/or silicone. The
covering 106 and/or the liner 108 may also comprise any plastic or
polymeric material, desirably a somewhat hard but flexible plastic
or polymeric material. The covering 106 and/or the liner 108 may be
transparent or translucent, desirably substantially or partially
transparent.
[0127] The coverings and/or the liner of the present invention may
be made from a "textile" material, from a "non-textile" material,
or from a combination thereof. As used herein, the term "textile"
refers to a material, such as a yarn, that may be knitted, woven,
braided, or the like, into a structure, such as a hollow, tubular
structure. As used herein, the term "non-textile" refers to a
material formed by casting, molding, spinning or extruding
techniques to the exclusion of typical textile forming techniques,
such as braiding, weaving, knitting, and the like. In particular,
the covering 106 and/or the liner 108 may be constructed of any
suitable biocompatible materials, such as, but not limited to,
polymers and polymeric materials, including fillers such as metals,
carbon fibers, glass fibers or ceramics.
[0128] Useful covering 106 and/or liner 108 materials include, but
are not limited, polyethylene, polypropylene, polyvinyl chloride,
polytetrafluoroethylene (PTFE), including expanded
polytetrafluoroethylene (ePTFE), fluorinated ethylene propylene,
fluorinated ethylene propylene, polyvinyl acetate, polystyrene,
poly(ethylene terephthalate), naphthalene dicarboxylate
derivatives, such as polyethylene naphthalate, polybutylene
naphthalate, polytrimethylene naphthalate and trimethylenediol
naphthalate, polyurethane, polyurea, silicone rubbers, polyamides,
polyimides, polycarbonates, polyaldehydes, polyether ether ketone,
natural rubbers, polyester copolymers, styrene-butadiene
copolymers, polyethers, such as fully or partially halogenated
polyethers, silicones, and copolymers and combinations thereof.
[0129] The coating or coatings may be on the stent 20, components
of the stent 20, and combinations thereof. The stent components, in
part or in total, may be temporary, for example bioabsorbable,
biodegradable, and the like, or may be permanent (i.e., not
substantially bioabsorbable or biodegradable), for example the
above-described biocompatible metals, alloys and polymers.
[0130] Desirably, the stent 20 includes braided polyester
filaments, such as PET polyester filaments. Further, in some
applications, the stent 20 is desirably embedded in a coating of
silicone. Additional details of such desirable stents are described
in U.S. Pat. No. 6,162,244, the contents of which are incorporated
herein by reference.
[0131] When a silicone covering is used, the silicone may be
disposed on external surfaces of the stent 20 and/or on internal
surfaces of the stent 20. Such a silicone covering may be in the
form of a coating or film and may be suitably formed by dip-coating
the stent. Details of such dip-coating may be found in U.S. Pat.
No. 5,875,448, the contents of which are incorporated herein by
reference. Moreover, other techniques, such as spraying, may
suitably be used to form the silicone covering. After applying the
silicone coating or film to the stent, the silicone may be cured.
Desirably, the curing is low temperature curing. For example, the
curing desirably occurs from about room temperature to about
90.degree. C. for a short period of time which may be, for example,
from about 10 minutes or more to about 16 hours. The cured silicone
covering also may be sterilized by electronic beam radiation, gamma
radiation ethylene oxide treatment, and the like. Further details
of the curing and/or sterilization techniques may be found in U.S.
Pat. No. 6,099,562, the contents of which are incorporated herein
by reference. Argon plasma treatment of the cured silicone also may
be used. Argon plasma treatment of the cured silicone modifies the
surface of the cured silicone to, among other things, make the
surface less sticky.
[0132] Suitable textile materials for use in the present invention
may be formed from synthetic yarns that may be flat, shaped,
twisted, textured, pre-shrunk or un-shrunk. Synthetic biocompatible
yarns suitable for use in the present invention include, but are
not limited to, polyesters, including polyethylene terephthalate
(PET) polyesters, polypropylenes, polyethylenes, polyurethanes,
polyolefins, polyvinyls, polymethylacetates, polyamides,
naphthalene dicarboxylene derivatives, natural silk, and
polytetrafluoroethylenes. Moreover, at least one of the synthetic
yarns may be a metallic yarn or a glass or ceramic yarn or fiber.
Useful metallic yarns include those yarns made from or containing
stainless steel, platinum, gold, titanium, tantalum or a
Ni--Co--Cr-based alloy. The yarns may further include carbon, glass
or ceramic fibers. Desirably, the yarns are made from thermoplastic
materials including, but not limited to, polyesters,
polypropylenes, polyethylenes, polyurethanes, polynaphthalenes,
polytetrafluoroethylenes, and the like. The yarns may be of the
multifilament, monofilament or spun-types. As is well-known, the
type and denier of the yarn chosen may be selected in a manner
which forms a prosthesis and, more particularly, a vascular
structure having desirable properties.
[0133] The yarns for use in textile graft coverings of the present
invention may be knitted, woven, or braided in any manner known in
the art. The knit may be a circular knit or may be a flat knitted
tubular knit. Useful knits include, but are not limited to, a high
stretch knit, a locknit knit (which also is referred to as tricot
or jersey knit), reverse locknit knits, sharkskin knits, queenscord
knits, and velour knits. Useful high stretch, warp-knitted patterns
include those with multiple patterns of diagonally shifting yarns,
such as certain modified atlas knits which are described in U.S.
Pat. No. 6,540,773, the contents of which are incorporated herein
by reference. Other useful high-stretch, warp knitted patterns
include certain patterns with multiple needle underlap and one
needle overlap, such as those patterns described in U.S. Pat. No.
6,554,855 and U.S. Patent Application Publication No. 2003/0204241
A1, the contents of which are incorporated herein by reference.
U.S. Pat. No. 5,653,746, the contents of which are incorporated
herein by reference, further describes useful knits. Useful braids
include, but are not limited to, those described in U.S. Pat. No.
5,653,746, the contents of which are incorporated herein by
reference. Useful weaves include, but are not limited to, a plain
or regular weave, a basket weave, a twill weave, a satin weave, a
velour weave, a circular weave, a flat tubular weave, or the like.
Suitable textiles and methods for making the same are further
discussed in U.S. application Ser. No. 11,025,571, filed Dec. 29,
2004, the contents of which are incorporated herein by
reference.
[0134] In some embodiments, stent 20 may be treated with any
suitable therapeutic agent. Non-limiting examples of suitable
therapeutic agents include the following: anti-thrombogenic agents
(such as heparin, heparin derivatives, urokinase, and PPack
(dextrophenylalanine proline arginine chloromethylketone));
anti-proliferative agents (such as enoxaparin, angiopeptin,
monoclonal antibodies capable of blocking smooth muscle cell
proliferation, hirudin, and acetylsalicylic acid);
anti-inflammatory agents (such as dexamethasone, prednisolone,
corticosterone, budesonide, estrogen, sulfasalazine, and
mesalamine); antineoplastic/antiproliferative/anti-mitotic agents
(such as paclitaxel, 5-fluorouracil, cisplatin, vinblastine,
vincristine, epothilones, endostatin, angiostatin and thymidine
kinase inhibitors); anesthetic agents (such as lidocaine,
bupivacaine, and ropivacaine); anti-coagulants (such as
D-Phe-Pro-Arg chloromethyl keton, an RGD peptide-containing
compound, heparin, anti-thrombin compounds, platelet receptor
antagonists, anti-thrombin antibodies, anti-platelet receptor
antibodies, aspirin, prostaglandin inhibitors, platelet inhibitors,
and tick antiplatelet peptides); vascular cell growth promoters
(such as growth factor inhibitors, growth factor receptor
antagonists, transcriptional activators, and translational
promoters); vascular cell growth inhibitors (such as growth factor
inhibitors, growth factor receptor antagonists, transcriptional
repressors, translational repressors, replication inhibitors,
inhibitory antibodies, antibodies directed against growth factors,
bifunctional molecules consisting of a growth factor and a
cytotoxin, bifunctional molecules consisting of an antibody and a
cytotoxin); cholesterol-lowering agents; vasodilating agents; and
agents which interfere with endogenous vascoactive mechanisms.
[0135] Suitable stents and materials for stents for use in the
present invention include those discussed in U.S. application Ser.
No. 11/271,774, filed Nov. 10, 2005, U.S. application Ser. No.
11/365,324, filed Mar. 1, 2006, U.S. application Ser. No.
60/819,422, filed Jul. 7, 2006, U.S. application Ser. No.
11/437,889, filed May 19, 2006, U.S. application Ser. No.
11/437,455, filed May 19, 2006, and U.S. application Ser. No.
11/437,459, filed May 19, 2006, the contents of all of which are
incorporated herein by reference.
[0136] The stent 20 of the stent delivery systems of the present
invention may be delivered to a bodily lumen using any suitable
delivery device known in the art. In some embodiments, a wire is
used to deliver the stent to a bodily lumen. In other embodiments,
a rapid exchange catheter such as the rapid exchange catheter
disclosed in U.S. Pat. No. 6,592,549, the full contents of which
are incorporated by reference herein, may be used. In still other
embodiments, stent delivery may be through an endoscope. In yet
other embodiments, a delivery device is employed which includes a
fiber optic or a chip which allows visualization of the placement
of the stent. In still other embodiments, a balloon catheter may be
employed to deliver stent to the bodily lumen. It still other
embodiments, stent delivery may be unassisted (i.e., no wire or
endoscope is employed). Moreover, stent delivery device may have
variable stiffness.
[0137] While various embodiments of the present invention are
specifically illustrated and/or described herein, it will be
appreciated that modifications and variations of the present
invention may be effected by those skilled in the art without
departing from the spirit and intended scope of the invention.
* * * * *